A power amplifier is used to amplify radio frequency signals to be transmitted from an antenna of a wireless device such as a mobile telephone. A number of conventional power amplifiers employ bias circuitry that provides an inadequate bias signal level when the radio frequency signals reach a peak power level. As such, these conventional power amplifiers often suffer from output signal distortion at peak power levels. For example, the inadequate bias signal level results in amplitude modulation—amplitude modulation distortion that can cause an out-of-specification adjacent channel leakage ratio. Thus, a power amplifier system having a bias circuitry that provides adequate bias signal levels at all power levels is needed.